Cortical and juxtamedullary nephrons differ in the:

a. lengths of their nephron loops.

b. structure of the capillaries surrounding them.

c. structure of their renal corpuscles.

d. Both a and b are correct.

e. Both b and c are correct.

Video transcript

Welcome back, everyone. Our next question says, which of the following describes juxtamedullary nephrons. A. They are the most common type of nephrons. B, they have a relatively short loop of Henley C. They are present in all types of vertebrates or D. They have a large network of vas erecta. Well, let's recall what types of nephrons we have, we have the juxta medullary nephrons. So I'll just put juxta with a period. And the other kind are the cortical nephrons. And the easiest way to remember this is to remember that the cortical nephrons are primarily completely within the cortex. The very end of their loop of Henley, they go a little bit into the medulla, but mostly they are contained within the cortex. Whereas the juxtamedullary nephrons think of juxtaposition or putting together, dip down deep into the medulla. And what is the portion of the nephron that drops down to the lowest point? Well, that's the loop of Henley. So that helps us keep straight. What kind of loop of Henley do? These have? Well to dip down low, go all the way down to the Mandula, you need a long loop of Henley. And if you're combined mainly up in the upper layer of the cortex, like cortical neurons, nephrons, excuse me, you have a short loop of henley. So with that basic distinction, let's look through our answer. Choices. A they are the most common type of nephrons. Well, this is incorrect, cortical nephrons are the most common type. They make up about 85% of all nephrons. So choice A is not correct choice. B they have a relatively short loop of Henley. Well, as we kind of thought our way through below, this is also cortical nephrons. They are contained mostly within the upper cortex. They have short loops of Henley. That part that dips down to the lowest point. Choice C, they are present in all types of vertebrates. Well, this is also incorrect about juxta menage nephrons. They are present only in birds and mammals. So choice C not our correct answer. And now all we have left is choice D as our answer. They have a large network of vas reca this is correct. These are those long straight capillaries that surround the loop of Henley of the juxta me nephrons sort of like a mesh or think of a piece of crocheting or something around that loop. And they have the important function of maintaining the osmotic gradient, which is the all important qualification of the loop of Henley that allows a production of concentrated urine as you drop down into the medulla, the filtrate gets more and more and more concentrated. And then as you come back up, less concentrated, going down and then up through this gradient and the vas erecta helps maintain this because it allows this passage of water and Solus that maintains the gradient as you go down and then back up. So our statement that correctly describes juxtamedullary nephrons is choice D they have a large network of vasa recta. See you in the next video.